Why is 3-aminopentane achiral while 3-aminohexane is chiral?

Because 3-aminopentane does not have four different groups attached to the carbon and has a plane of symmetry, while 3-aminohexane has four different groups attached to the carbon and does not have a plane of symmetry.

Because 3-aminopentane has four different groups attached to the carbon and does not have a plane of symmetry, while 3-aminohexane does not have four different groups attached to the carbon and has a plane of symmetry.

Because 3-aminopentane has four different groups attached to the carbon and has a plane of symmetry, while 3-aminohexane does not have four different groups attached to the carbon and does not have a plane of symmetry.

Because 3-aminopentane does not have four different groups attached to the carbon and does not have a plane of symmetry, while 3-aminohexane has four different groups attached to the carbon and has a plane of symmetry.